There are several modular shelving systems on the market today wherein any desired number of shelving units are positioned in a group depending on the amount of storage needed. In order to conserve space, one or more of the shelving units may be mobile. Typically, each mobile unit is provided with rollers that roll on tracks permanently secured to the floor.
In one of the most popular systems on the market, the shelving units move laterally (sideways) rather than in the longitudinal direction. In a system of this nature, access to a particular shelf assembly is hampered since in most instances more than one of the assemblies must be moved. Also, there is always one shelf assembly left open and thus neither a fully closed system nor full space utilization is attained.
A similar type of system has been proposed in the prior U.S. Patent to Foulkes U.S. Pat. No. 2,166,704, issued July 18, 1939. This system has essentially the same drawbacks of being track supported, not being capable of being fully closed and not making full utilization of floor space.
Thus, there is a need first for a shelving system that operates on a flat surface without the need for the expensive track system used by the prior art. When a track system is provided, the purchaser is faced with either providing a false floor and ramp in order to conceal the tracks, or leaving the tracks exposed providing a safety hazard. Secondly, there is a need for a system that can be fully closed when the units are positioned in juxtaposition. Only one unit for every two or three should have to be movable for access to any shelf in the system. Such a system is not only more aesthetically pleasing and more secure, but also maximizes utilization of floor space and is lowest in cost.